JP2010200008A - Camera module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a durable camera module 1 capable of constantly providing high-quality image information by securing long-term reliability in image an information processing section. <P>SOLUTION: The camera module 1 includes a lens 2, a barrel 3 for holding the lens 2, an image pickup device 4 for capturing a subject image formed by the lens 2 by a light reception surface, a plurality of circuit boards 6, substrate holding members abutting on the plurality of circuit boards 6 while being overlapped alternately for arrangement, and housings 8, 9 for storing the lens 2, the barrel 3, the image pickup device 4, the plurality of circuit boards 6, and the substrate holding members 7a, 7b, 10. In the camera module 1. The plurality of circuit boards 6 include image pickup devices, fixing substrates 6a, and the plurality of circuit boards 6 and the substrate holding members 7a, 7b, 10 are overlapped in the direction of an optical axis of the lens for arrangement. A laminate of the plurality of circuit boards 6a, 6b and the substrate holding members 7a, 7b, 10 is pressed to the side of the image pickup device by the housing 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera module.

  A camera module equipped with an electronic imaging device that is compact and has durability such as vibration resistance and impact resistance is used in a mobile phone with a camera or an in-vehicle camera. In general, as shown in FIG. 6, a camera module including such an electronic imaging device includes a lens, and a lens barrel unit including a lens barrel 3 that holds the lens and secures an imaging distance of the lens, An imaging element 4 such as a CCD (Charge Couplde Devices) or CMOS (Complementary Metal Oxide Semiconductor) that captures a subject image formed by a lens and converts it into an electrical signal, and an electrical signal from the imaging element 4 is stored in a storage device or an external device. A camera module main body having a signal processing unit (circuit board 6) to be transmitted to the receiving device and an imaging unit including an imaging device holder 5 that holds the imaging device 4 and the like and is fixed to the camera module 1, and It consists of casings (front cover 8 and rear cover 9) to be accommodated.

  In such a camera module, first, a lens is positioned and fixed to a lens barrel to produce a lens barrel unit, and an image sensor and a signal processing unit are arranged in an image sensor holder to produce an image sensor unit. Next, the lens barrel unit and the imaging unit are assembled while being positioned and fixed to the casing. If the light receiving surface of the image sensor is displaced or tilted with respect to the optical axis of the lens during this assembly, image position displacement or image blurring is likely to occur, and the image quality captured by the camera module will deteriorate. Strict assembly has been made.

  The smaller the camera module, the greater the influence of the position and tilt of the light-receiving surface of the image sensor on the optical axis of the lens, and the importance of accurate assembly is increasing. The axis and the imaging element are 20 μm or less.

  Patent Document 1 discloses a camera module manufacturing method and a camera module manufacturing apparatus that can be precisely adjusted and fixed so that the light receiving surface of the imaging element is accurately arranged with respect to the optical axis of such a lens. Proposed. In this method of manufacturing a camera module, the positions of the lens barrel unit and the imaging unit are provisionally determined using reflection of the light-receiving surface of the imaging element with respect to the laser beam, and a test pattern is captured by the provisionally determined camera module. The lens barrel unit and the imaging unit are positioned by 6-axis adjustment based on the photographed image, and are fixed as they are by ultraviolet curable resin.

  On the other hand, a circuit board built in an electronic imaging camera module has a function of storing and transmitting imaging information. For this reason, the circuit board includes an electronic component having a heat generating action (referred to as a heat generating component). When a member of the optical system from the lens to the image sensor is heated by the heat-generating component, the optical system may be distorted due to thermal distortion of the member, resulting in blurring of the captured image, and image quality may be degraded.

  Patent Document 2 discloses a technique for reducing the influence of heat-generating components in a vehicle-mounted camera that can wirelessly transmit captured image information. In this vehicle-mounted camera, the image pickup unit and the heat generating component on the circuit board are arranged apart from each other, and a heat radiating unit is provided in the vicinity of the heat generating unit. This camera can prevent deterioration of image quality due to at least self-heating during use.

  Patent Document 3 discloses a video camera using a multilayer flexible substrate. The imaging information processing unit of the camera module includes a plurality of circuit boards (rigid boards), and a multilayer board in which the rigid boards are stacked by a flexible board that transmits and receives signals and the like between the rigid boards. A flexible substrate is used. Thus, a video camera that realizes downsizing of the imaging information processing unit is disclosed.

  If the manufacturing method of the camera module disclosed in Patent Document 1 is used, the displacement of the arrangement and inclination of the optical axis of the lens and the imaging surface of the imaging device can be suppressed to a very small range. However, the lens and the image sensor can be accurately arranged at the time of manufacture, and the deterioration of the image quality due to the function deterioration during use has been a problem. In particular, in-vehicle camera modules and the like are not only greatly affected by vibration and shock during use, but also require durability that is the same as the life of the vehicle.

  In the camera module described in Patent Document 2, countermeasures against self-heating of the circuit board portion are taken. It is also important to downsize the camera module described in the patent document. However, if these camera modules are used in a mild environment, they can exhibit excellent performance, but no special measures have been taken against vibrations, shocks, and severe temperature changes from outside.

  An example of a conventional camera module that does not take measures against the vibration or shock of the circuit board portion will be described with reference to FIG. FIG. 6 is a cut model of the in-vehicle camera module, and is a perspective view of the cut model in which the front cover 8 and the rear cover 9 which are housings are cut in half and removed. The lens 2 is exposed in an invisible part on the lower side of the figure, and a lens barrel 3 that holds the lens, an image pickup device that is not shown because it is inside the image pickup holder 5, and a circuit board that is coupled to the image pickup device (Sensor substrate) 6a and an imaging holder 5 fixed to the lens barrel 3, and an imaging that is a circuit board that directly connects to the imaging device and processes imaging information from the imaging device to store, transmit, etc. The information processing unit includes an element fixing substrate 6a and circuit boards 6b and 6c arranged to overlap the image sensor fixing substrate 6a. The imaging element fixing substrate 6a is also a kind of circuit board, and the imaging element fixing substrate 6a and the circuit boards 6b and 6c may be collectively referred to as a circuit board 6. Further, the imaging element fixing substrate 6a may be simply referred to as a circuit substrate 6a. The circuit board (rigid board) 6 is connected and determined by a wide and relatively rigid flexible bond line group (flexible board). If there is no violent vibration or impact, the circuit boards (rigid boards) 6a, 6b, 6c are fixed in position by the connecting wire group (flexible board), and this camera module can exhibit sufficiently stable performance.

  However, on the circuit boards (rigid boards) 6b and 6c, connectors, large IC chips with relatively heavy weight, and the like are loaded. When severe vibration or impact is applied, the flexible board is deformed, and the circuit board 6b. , 6c collides with or slides on an adjacent circuit board or housing. If the circuit boards 6b and 6c collide, the circuit boards 6b and 6c may be damaged or a connection failure may occur. Further, when the circuit boards 6b and 6c are in sliding contact with each other, wear powder is generated and adheres to the board, causing malfunction of the 6b and 6c.

  As a countermeasure against the collision and sliding contact of the circuit board, a camera module provided with a substrate holder 13 as shown in a perspective view of the main body portion of the camera module in FIG. 5 can be considered. The substrate holder 13 is made of a U-shaped sheet metal, and each circuit board 6 and the end of the lens barrel 3 are inserted and fixed to the substrate holder 13 to stabilize each circuit board 6a, 6b, 6c. In this way, the positions of the circuit boards 6 are fixed with respect to the lens barrel, and no collision or sliding contact occurs.

  However, in a recent small camera module, the size of the circuit board 6 is 10 mm or less, the distance between the boards is only about 2 to 5 mm, and each circuit board 6 and the mirror are placed in the corresponding fixing holes of the sheet metal 13. It is not easy to insert the end of the tube 3. This insertion work takes tens of seconds even for a skilled worker. Further, if the fixing hole of the sheet metal 13 is enlarged for easy assembly, the end portion inserted into the fixing hole due to impact or vibration is likely to come off, and the fixing reliability of each circuit board 6 is impaired. It is an important issue in a small camera module to prevent collision and sliding contact between circuit boards or between a board and a member such as a housing and to efficiently manufacture a durable camera module.

  In view of the above problems, an object of the present invention is to provide a durable camera module that can ensure long-term reliability in an image information processing unit and can always provide high-quality image information.

  The present invention includes a lens, a lens barrel that holds the lens, an imaging element that captures a subject image formed by the lens on a light receiving surface, a plurality of circuit boards, and at least one of the plurality of circuit boards. A substrate holding member that is in contact with the circuit board and arranged alternately with the plurality of circuit boards; and the lens, the lens barrel, the imaging device, the plurality of circuit boards, and the board holding member. A plurality of circuit boards including an imaging element fixing board on which the imaging element is fixed, and the plurality of circuit boards and the board holding member are light beams of the lens. The camera module, wherein the plurality of circuit boards and the board holding member are pressed toward the image sensor by the housing. .

  In a preferred aspect of the present invention, the laminated body in which the plurality of circuit boards and the substrate holding member are arranged to be covered is covered with a conductive covering member.

  In a preferred aspect of the present invention, the camera module is characterized in that a wear preventing member for preventing wear due to sliding of the circuit board with the covering member is disposed in a gap between the circuit board and the covering member. It is.

  In a preferred aspect of the present invention, the substrate holding member is divided into a plurality of parts.

  In a preferred embodiment of the present invention, at least one of the substrate holding members includes an elastic body.

  In a preferred aspect of the present invention, the substrate holding member includes a porous resin or a porous resin composite material.

  In a preferred aspect of the present invention, the board holding member protrudes toward the housing from the side edge of the adjacent circuit board.

  In a preferred aspect of the present invention, the substrate holding member is disposed between the circuit board and the housing, the first substrate holding member made of a heat insulating material disposed in the gap between the plurality of circuit boards. And a second substrate holding member having higher thermal conductivity than the first substrate holding member.

  According to a preferred aspect of the present invention, the plurality of circuit boards perform at least one of storage of an image signal received from the image sensor, predetermined image processing for the image signal, and transmission of the image signal to the outside. The camera module including a circuit board.

  ADVANTAGE OF THE INVENTION According to this invention, the durable camera module which can ensure long-term reliability in an image information processing part, and can always provide high quality image information can be provided.

It is sectional drawing of the embodiment of the camera module which concerns on this invention. It is a perspective view of the cut model which cut a part of housing part of another example of an embodiment of a camera module concerning the present invention. It is a perspective view of the main-body part of the embodiment example of the camera module shown in FIG. It is the perspective view of the cut model which cut the housing part of the camera module shown in FIG. 1 half. It is a perspective view of the main-body part of the conventional camera module. It is a perspective view of the conventional camera module.

  An embodiment of a camera module according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of an embodiment of a camera module of the present invention. FIG. 2 is a perspective view of a cut model of an embodiment different from the camera module shown in FIG. 1 of the camera module according to the present invention. FIG. 3 is a perspective view showing a main body portion of the embodiment of the camera module shown in FIG. FIG. 4 is a perspective view of a cut model in which the housing portion of the camera module shown in FIG. 1 is cut in half.

  The camera module 1 of the embodiment shown in FIGS. 1 and 2 includes a lens barrel 2 that holds a lens 2 and adjusts the focal position of light incident from the lens as an optical system, and performs imaging as an imaging information processing system. The element 4, a plurality of circuit boards 6 coupled to the element 4, an imaging element holder 5 that holds the imaging element 4 and the circuit board 6, and a substrate that is alternately stacked between the plurality of circuit boards 6 A holding member is provided. The circuit board 6 receives an image signal from the image sensor 4 and obtains image information as an image sensor fixed board (sensor board) 6a, and further processes image information from the image sensor fixed board 6a or stores it in a storage device. Circuit boards 6b and 6c for transmitting image information to the outside of the camera module. The circuit boards 6a, 6b and 6c are also called rigid boards and are rigid circuit boards. On the other hand, a group of connection lines that connect the circuit boards 6a, 6b, and 6c to transmit and receive signals and power is called a flexible flexible board 61.

  In this embodiment, three circuit boards 6a, 6b, and 6c are coupled by a flexible board 61 in the order of the imaging element fixing board 6a, the circuit board 6c, and the circuit board 6b. The circuit boards 6a, 6b, and 6c are stacked at intervals from the imaging element 4 side in the order of the imaging element fixing board 6a, the circuit board 6b, and the circuit board 6c. In this embodiment, the circuit board includes three circuit boards. However, the circuit board according to the present invention may have a plurality of circuit boards, and may have a laminated structure of two sheets or a laminated structure of four or more sheets.

  As in the embodiment shown in FIGS. 1 and 2, the imaging element fixing substrates 6a, 6b, and 6c and the first and second substrate holding members 7a, 7b, and 10 are overlapped in the same direction as the optical axis direction of the lens. The laminated body of the circuit boards 6a, 6b, 6c and the board holding members 7a, 7b, 10 is pressed toward the image sensor 4 by the housing (rear cover 9). For example, the second substrate holding member 10 is an elastic body, and the rear cover 9 presses the second substrate holding member 10 in a state where the front cover 8 and the rear cover 9 are attached. The image sensor fixing substrate 6a is pressed. In this case, since the optical system is fixed to the front cover 8, both the optical system and the imaging information processing system are fixed by the pressing force, so that they do not collide or slide. In the embodiment shown in FIG. 2, the covering member 11 is not provided. However, the same applies to the embodiment including the covering member 11 as shown in FIG.

  In the embodiment shown in FIGS. 1 and 2, the first substrate holding member 7a is disposed in the gap between the image sensor fixing substrate 6a and the circuit substrate 6b so as to be in contact with the circuit substrates 6a and 6b. The first substrate holding member 7a preferably has a width that covers the entire surface of the circuit board 6a and the circuit board 6b facing the first substrate holding member 7a. In the gap between the circuit board 6b and the circuit board 6c, a first board holding member 7b is disposed so as to be in contact with each circuit board. The first substrate holding member 7b preferably has a width that covers the entire surface of the circuit board 6b and the circuit board 6c facing the first substrate holding member 7b. The substrate holding members 7a and 7b are made of a heat insulating material and are preferably a porous resin or a porous composite material. For example, foamed polyurethane, foamed polystyrene, foamed polyethylene, or a composite material obtained by mixing these foamed resins with an inorganic material is used. These first substrate holding members 7a and 7b, in addition to heat insulation, collide or slide the circuit boards 6a, 6b and 6c, the image pickup device 4, and the image pickup device holder 5 against vibration and shock of the camera module. It is preferable to have rigidity and elasticity to prevent the above. Since the surfaces of the circuit boards 6a and 6b are often conductive, the surfaces of the first board holding members 7a and 7b are preferably insulators. It is possible to prevent malfunction due to electric leakage between the surface of the circuit boards 6a and 6b and the contact surface of the first board holding members 7a and 7b.

  In the gap between the circuit board 6c and the inner surface of the rear cover 9, which is a housing, the second board holding member 10 is disposed so as to be in contact with the circuit board 6c and the inner surface of the rear cover 9. The second substrate holding member 10 is wide enough to cover the entire surface side facing the second substrate holding member 10 of the circuit board 6c, and the second substrate holding member 10 is made of a heat conductive material having elasticity. It is preferable. The heat transfer material here means a material having better heat transfer than the first substrate holding members 7a and 7b. The surface of the second substrate holding member 10 in contact with the circuit board 6c preferably has an insulating property like the first substrate holding members 7a and 7b. The surface of the circuit board 6c is often conductive, and if the surface of the conductive substrate holding member 10 is in contact with this, it may cause malfunction due to electric leakage.

  The imaging information processing system has a heat generating member such as an IC substrate that generates heat (for example, a central processing unit including a field programmable gate array (FPGA)). The included optical system may be heated to affect the focal length of the optical system, the optical axis, and the arrangement of the image sensor 4. For this reason, the circuit board (corresponding to the circuit board 6c in this embodiment) on which a member that generates heat is mounted among the circuit boards of the imaging information processing system is the farthest from the imaging element 4 (optical system), and the rear cover 9 It is arranged at the position facing. And the 1st board | substrate holding members 7a and 7b arrange | positioned between the circuit board 7c and the image pick-up element 4 shall have heat insulation. Then, the heat generation in the circuit board 7c hardly affects not only the optical system but also the circuit boards 6a and 6b. On the other hand, heat generated on the circuit board 7 c is transferred to the rear cover 9 by the second board holding member 10 and is radiated to the outside from the rear cover 9.

  The heat conductive material as the second substrate holding member 10 has a two-layer structure, for example, and the surface in contact with the circuit board 6c is a thin flexible and insulating resin sheet or porous resin sheet, for example, polyester, Polystyrene, polyethylene, polyurethane, or a foamed resin sheet thereof is used. The rear cover 9 side of the substrate holding member 10 is preferably made of aluminum or steel having good heat conductivity, a corrugated metal plate with elastic body, and the substrate holding member 10 preferably has a structure having elasticity and heat conductivity. As an example of the second substrate holding member 10 having a one-layer structure, a single-layer resin sheet or a porous resin sheet is used, and a portion of the resin sheet or the porous resin sheet facing the heat generation portion of the circuit board 6c is directed to the rear cover 9 side. It is also possible to promote heat dissipation by providing a through hole. In particular, as a method of using the camera module, when the second substrate holding member 10 is disposed on the circuit board 6c, convection heat transfer can be used, which is effective. From the viewpoint of ensuring heat conductivity, the gap between the circuit board 6c and the rear cover 9 is preferably thin.

  In the embodiment shown in FIG. 1, as shown in FIGS. 3 and 4, the laminate of the circuit boards 6 a, 6 b, 6 c and the board holding member is covered with a conductive covering member 11. The circuit boards 6a, 6b, and 6c may emit unintended electromagnetic waves, and the covering member 11 has a function of not transmitting these electromagnetic waves to the outside. In addition, it can block electromagnetic waves entering from the outside of the camera module and prevent malfunction of the circuit boards 6a, 6b, 6c. Furthermore, the covering member 11 can prevent a short circuit due to static electricity between the circuit boards 6a, 6b, 6c and the housing such as the rear cover 9. In order to effectively shield electromagnetic waves and prevent short circuits, it is preferable to connect the covering member 11 to the ground wire of the camera module 1. The covering member 11 is preferably made of metal, and may be made of a normal thin sheet metal or mesh as long as it has the above function. In addition, when the 2nd board | substrate holding member 10 contains a metal, about the part which coat | covers the 2nd board | substrate holding member 10 of the coating | coated member 11, the metal part currently used for the 2nd board | substrate holding member 10 is combined. I can do it.

  As shown in FIG. 1, a wear preventing member 12 is provided in a gap between portions of the covering member 11 facing the circuit boards 6a, 6b, and 6c (close to the circuit boards 6a, 6b, and 6c). preferable. The wear preventing member 12 prevents the covering member 11 and the circuit boards 6a, 6b, and 6c from sliding due to the vibration and impact of the camera module, and the circuit boards 6a, 6b, and 6c from being worn or damaged. If even part of the circuit boards 6a, 6b, 6c are worn, the abrasion powder adheres to the circuit boards 6a, 6b, 6c, wirings, etc., and the circuit is liable to malfunction. The wear prevention member 12 does not need to be disposed on the entire surface of the covering member 11, and only needs to cover a portion where the end portions of the circuit boards 6 a, 6 b, 6 c are opposed to the covering member 11. For example, a Teflon (registered trademark) or polyolefin-based sheet or film that does not easily wear when sliding on the covering member 11 is used as the wear preventing member 12 of the circuit boards 6 a, 6 b, 6 c facing the covering member 11. It may be arranged only at the end.

  Instead of disposing the wear preventing member 12 in the gap between the covering member 11 and the circuit boards 6a, 6b, 6c, the first and second board holding members are placed closer to the housing than the side edges of the circuit boards 6a, 6b, 6c. The covering member 11 and the circuit boards 6a, 6b, and 6c may be made difficult to slide even if the camera module is vibrated or shocked. In this case, it is particularly preferable if the first and second substrate holding members are elastic members made of polyurethane foam or polyethylene foam and have a structure that wraps the side edges of the circuit boards 6a, 6b, and 6c. .

DESCRIPTION OF SYMBOLS 1 Camera module 2 Lens 3 Lens tube 4 Image pick-up element 5 Image pick-up element holder 6, 6b, 6c Circuit board (rigid board)
6a Image sensor fixed board (circuit board, rigid board)
61 Flexible substrate 62 Connector 63 Heating member 7, 7a, 7b First holding member 8 Front cover (housing)
9 Rear cover (housing)
DESCRIPTION OF SYMBOLS 10 2nd holding member 11 Covering member 12 Wear prevention member 13 Substrate holder

Japanese Patent No. 4140491 JP 2005-079931 A JP 2001-275022 A

Claims (9)

A lens,
A lens barrel for holding the lens;
An image sensor that images a subject image formed by the lens on a light receiving surface;
A plurality of circuit boards;
A substrate holding member that is in contact with at least one circuit substrate among the plurality of circuit substrates and is alternately stacked with the plurality of circuit substrates;
A housing for housing the lens, the lens barrel, the imaging device, the plurality of circuit boards, and the board holding member;
A camera module comprising:
The plurality of circuit boards include an image sensor fixing board on which the image sensor is fixed,
The plurality of circuit boards and the board holding member are arranged so as to overlap in the optical axis direction of the lens,
The camera module, wherein the plurality of circuit boards and the board holding member are pressed toward the imaging element by the housing.   2. The camera module according to claim 1, wherein the laminated body in which the plurality of circuit boards and the board holding member are overlapped is covered with a conductive covering member.   The camera module according to claim 2, wherein a wear preventing member for preventing wear due to sliding of the circuit board with the covering member is disposed in a gap between the circuit board and the covering member. .   The camera module according to claim 1, wherein the substrate holding member is divided into a plurality of parts.   The camera module according to claim 1, wherein at least one of the substrate holding members includes an elastic body.   The camera module according to claim 1, wherein the substrate holding member includes a porous resin or a porous resin composite material.   The camera module according to claim 1, wherein the substrate holding member protrudes toward the housing from a side surface end portion of the adjacent circuit substrate.   The substrate holding member is disposed in a gap between the plurality of circuit boards. The first substrate holding member made of a heat insulating material is disposed between the circuit board and the housing. The camera module according to claim 1, further comprising a second substrate holding member having higher thermal conductivity than the second substrate holding member.   The plurality of circuit boards include a circuit board that performs at least one of storage of an imaging signal received from the imaging element, predetermined image processing on the imaging signal, and transmission of the imaging signal to the outside. The camera module according to any one of claims 1 to 8.

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